The Creation Debate-Part 10

More fascinating details about feathers that make their evolution from reptilian scales improbable at best.

Editor’s note: In June 1990 The John Ankerberg Show taped a series of interviews with men from several branches of the sciences regarding the evidence for creation. For technical reasons we were unable to air these interview. Nevertheless, we have decided to re­lease portions of these interviews in a series of articles so you could read the arguments that were being made at that time—more than a decade ago.

Considerable effort has been made to quote the gentlemen correctly. We have at­tempted to find the correct spelling of the scientific terms used. However, the reader should keep in mind that this is a transcription of oral interviews. Mistakes in spelling and in the technical language should be laid at the feet of the editor.

The Creation Debate - Part 10Feathers - Part 2

Dr. Kurt Wise: Is there any evidence, David, for archaeopteryx having all three feather types of modern birds?

Dr. David Menton: Not really. We mentioned the three feathers that are common in birds; the down-feather, the filoplume and the contour feather. I’m not aware that a true down-feather has been observed; that would of course be covered by the contour feathers as would filoplumes. We don’t even notice filoplumes on a chicken until we pluck the bird, and then we see the little filoplumes emerging. There is no reason to doubt that they are there, but we do not have evidence that they are.

There is, on the other hand, a wide variety of contour feathers in birds, even including small contour feathers on the head. It wasn’t a scaly head, I repeat again, as it is so often pictured in the drawings to emphasize its reptilian character, at least one of the specimens gives reason to believe that there were small contour feathers in the head. So, no, I would think we are talking primarily about contour feathers.

Wise: Do all living birds have all three types of feathers?

Menton: I don’t know.

Dr. Duane Gish: Well, non-flying birds would not have the asymmetric primary feathers. They’re not asymmetric.

Wise: Yes, but they would be symmetric. They would have feathers anyway.

Gish: Yes, they would be symmetric. They’re non-flying birds.

Wise: Another question. You find it difficult to construct at least in your mind a feather from a scale by evolution. How about in the evolutionary literature? Are you aware of a reasonable scenario whereby a feather can be produced from a scale?

Menton: Well, of course, speculation runs rife in the literature. There are people who can imagine almost anything. The standard scenario is, as I believe you’ve already sug­gested, that a reptilian scale somehow elongated even beyond what we see in reptilian scales, that it became frayed, as it were, thus looking like the barbs that we see in the wings. One investigator, indeed, has gone so far as to suggest that flight evolved by birds using their wings to catch insects; that they were pursorial, they ran around on the ground, chasing insects, holding their forelimbs out in front of them, and that feathers evolved as a mechanism rather like a flyswatter to capture insects and that this would then benefit from having a scale get ever longer and more like a flyswatter.

This sort of speculation of course, is virtually without limit. I think one of the problems with evolution is that there is nothing to really limit our speculation. There’s no critical ex­periment that can be done to really say that thus far, and no further.

There obviously is no detailed mechanism, to account for how the feather would pro­gressively change in this way, what sorts of genes would be involved, how this would im­pact on differential reproduction, which finally natural selection has to result in. There are merely those who can imagine a scale getting longer and longer, becoming more and more frayed, and being used perhaps for thermal insulation first or being used as a fly catcher and only later finding its use in flight.

But it takes a lot more than feathers to fly. Years ago when I made model airplanes, I was always a bit chagrined to learn that when I would go out and give the plane a toss, it would often go down and hit the ground, or would do a loop-de-loop. The reason for this was, the center of gravity wasn’t just right. We had to change the position of the wing. You can imagine, if origin of flight were left up to chance, it would be possible, perhaps, to come up with wings, and to come up with feathers, and to come up with reduced body weight, and the powerful muscles of the bird which move the bird in flight, comprising 30% of the body weight of the bird. But would we have the center of gravity right? Would our model airplane fly, as it were? If it could fly, could it navigate? Would it have the wing-brain coordi­nation? Would the individual feathers be under muscular control to work to increase lift or to allow flapping flight? There are so many things that are required for a bird to fly.

Unlike reptiles, birds have a very high metabolic rate. They have a high body tempera­ture. They have a high heartbeat rate. In this respect, they certainly differ significantly from all known reptiles. They have an unusual lung that is quite unlike any other organism. It is called a double-tide lung. The bird oxygenates air both on the inhalation stroke and on the exhalation stroke; that is, the air comes in through the trachea, passes right through the lung and out into air sacs, that are tucked away, not only among the muscles in the body of the bird, but even inside of the bones, which are hollow. In addition to reducing weight in the bird (someone once described the bird as a bag of air), as the bird flies this can then propel the air back out through the lungs and it is able to oxygenate its blood on the inhala­tion and the exhalation stroke.

This of course is very useful in powered flight. The metabolic requirements of flight are very high. Anyone who has ever attempted to fly by putting wings on his arms and flapping vigorously knows that it takes an immense amount of effort to get off the ground. I don’t believe anyone has ever quite managed to lift himself off the ground in this way. So the requirements of flight are many-fold besides feathers. I think Duane has joked around from time to time that its not good enough to just stick a bunch of feathers in a reptile, kick it in the tail and expect it to fly. Many other things are required.

Look at the molting problem alone. Feathers are subject to damage. They wear out just like hairs. And again just like hairs, they are sloughed on a regular basis. But feathers, at least the larger ones, cannot be sloughed just any old way, as hairs are sloughed from our scalp one by one. The larger feathers need to be shed in pairs, and they need to grow back in pairs. If this were not the case, the bird would then become asymmetric in terms of its feathers, and would not be able to fly properly.

So, there are so many extraordinarily clever, intricate, integrated design features in a bird and in its feathers, that I simply lack the credulity to believe that through random changes and differential reproduction we could go from a reptile to a bird, or to be more specific, that we could go from a reptilian scale to a feather. And, indeed, the evidence is not there. Certainly not for the scale-to-feather transition.

Gish: I might add that I was reading a book by Alan Feduccia, who is certainly one of the world’s leading experts on birds, probably knows as much about birds as anyone else in the world, and he did not offer any explanation on the origin of the feather. But he did suggest that two other investigators had suggested rather reasonable explanations, so I secured these two papers that he referred to and read them. I found them to be nothing more than highly imaginative speculation. There is no, absolutely no empirical evidence for either process, and there were a number of difficulties even in these speculations—that alpha-keratin and beta-keratin we find in the scales differed in some cases as I remember.

But it was just empty speculations or we might say empty rhetoric. There is no real explanation there that would satisfy, I think, any adequate scientific requirement.